The present invention relates to a method for evaluating the underwater effectiveness of a fishing lure and, in particular, relates to a system for reproducing the underwater color of the fishing lure as corrected for the light-filtering aspects of the water, the particular type of fish being targeted, and the nominal presentation distance from the lure to the fish in accordance with the underwater topography and the method of fishing being used.
It is known that the color of objects can shift when they are moved to a position underneath the water and that the degree of this shift can depend on the turbidity and depth of the water. In the field of under-water photography, in particular, it has been suggested that the water acts like a filter so that water of a blue-green color, for example, will absorb colors at the red end of the spectrum thereby causing progressively less red and orange light to reach an object as its underwater depth increases. This effect has apparently been reported in a publication of the Eastman Kodak Company entitled "The Fifth and Sixth Here's How," combined edition, pages 38-39 (1977). The Kodak article notes that there is one interesting exception to this effect, which is that fluorescent dyes retain their normal hue even at depths where a non-fluorescent dye of the same color would fade away.
This underwater color-shifting effect is known to fishermen of the more sophisticated type. Hence, author Paul Johnson, in his book entitled "The Scientific Angler," Charles Scribner's Sons, pages 89-91 and 162-163, NY (1984), reports on an experiment in which a color plate with seven fluorescent and seven non-fluorescent colors were photographed first above the surface of the water and then again at a specified depth beneath the water. Using color photographs to illustrate his findings, Johnson noted that whereas the non-fluorescent red and orange colors tended to turn black at relatively shallow depths, the fluorescent red and oranges, on the other hand, tended to hold their color at least to very large depths even though both the fluorescent and non-fluorescent colors looked substantially the same above the water. Substantially less color shift was observed with the blues and greens. The brightest color, from long-distances in blue water, was fluorescent yellow. Johnson further confirmed that as the level of water turbidity increased, that is, as the spectral character of the water went from being clear to being green, the difference in color shifts between the fluorescent and non-fluorescent colors occurred much more quickly.
This increase in color shift for increasing water turbidity is a factor of particular significance for anadromous fish. These fish, which include king salmon, silver salmon, steelhead trout and sea-run cutthroat trout, travel from the sea up small rivers and streams in order to spawn. This activity has commercially important consequences, and it has been estimated, for example, that over a hundred thousand fishermen in this country alone engage themselves in the pursuit of these cold-water "sea-run" fish. Since these fish tend to lie deep in turbid, rapidly moving water, lures that are used to catch these fish are particularly susceptible to the color shifting effect. In such water, light components of ultraviolet, orange, red, and infrared wavelength may fail to penetrate even to depths of 3-5 feet.
Based on the recognition that certain fishing lure colors are more effective than others, various systems have been developed to assist the fisherman in the selection of an optimal fishing lure color. One early type of system described in Wilbourn U.S. Pat. No. 2,809,458 provided a yellow weight suspended from a cord with a succession of color bands marked along the length of the cord. To use this device, the fisherman lowered the weight into the water until it disappeared from view and then identified the color of the band of cord then present at the surface of the water as representing the optimal color of the fishing lure. This device, in other words, assumed that there was a one-to-one correspondence between water opacity and the optimal fishing lure color but did not correct for other factors that were recognized as being important including the color-related filtering effect of the water and the intended depth at which the fishing lure was to be used.
In contrast to the relatively simple early device just described, later systems for indicating the optimal fishing lure color have relied on elaborate, expensive and easily-damaged equipment. In these later systems, typically a submersible probe unit is lowered into the water to the depth at which the lure will be used and a particular aspect of the light that reaches the probing unit at the specified depth is then electronically measured. This information is conveyed via cable to a readout instrument above the water surface.
In the system shown in McLaughlin et al. U.S. Pat. No. 3,897,157, for example, the probing unit includes a stacked assembly of color filters and photo-cells which are designed to measure the intensity of three different color components of the underwater light, namely red, blue and yellow. In accordance with the teachings of McLaughlin, the optimal color of the fishing lure corresponds to that one of the three color components that has the highest relative intensity at the specified depth.
A comparable but somewhat different system is shown in Hill U.S. Pat. No. 4,693,028, wherein a submersible photometer is used to measure the level of light transmittance (on a scale of 0 to 100%) at the specified depth. In addition, the turbidity level of the water (i.e., clear, stained or muddy) is separately determined and these two levels are then correlated, by means of a chart provided on the panel of the readout instrument, with an optimal color for the fishing lure (the optimal non-fluorescent color and the optimal fluorescent color are separately indicated and the instrument needle, if it falls on a line between two charted colors, is presumed to signify that either color is optimal).
In respect to the Hill system, in order to decide what color on the chart should correspond with a particular pair of measured light levels, Hill teaches that it is necessary to actually conduct carefully controlled tests with fish of the targeted type in order to draw a valid correlation, that is, in order to determine what colors are actually preferred by the targeted fish when presented with the specified light levels. Although the amount of testing required to make this correlation appears from his patent to be quite extensive, Hill supports his approach by pointing out that there appears to be little agreement as to how the color perception of fish either compares to that of humans or relates to environmental factors. Using the McLaughlin system as an example, Hill points out that McLaughlin presumes that fish see light as does a human whereas another researcher, F. A. Brown, concluded that at least with respect to bass, colors are seen by these fish in about the way that the same colors would appear to a person if viewed by that person through a yellowish filter. Hill further points out that McLaughlin assumes that the color component or wavelength that is the most intense at the specified depth is that which will be most attractive to the fish whereas another researcher, Professor Don McCoy, concluded that at least with respect to bass, some wavelengths were inherently more attractive to bass than other wavelengths regardless of relative brightness. Unfortunately, under the approach suggested by Hill, a large expenditure of effort is required to perform the studies needed to draw valid correlations from the collected data. Despite his own extensive investigations, Hill arrives at results that are only valid for one type of fish, namely bass. Hill does not indicate what data correlations are valid for other types of fish generally or for anadromous fish in particular.
A more fundamental difficulty that applies to each of the prior art approaches described hereinabove is the implicit assumption that the fisherman will always have on hand a lure that precisely matches the indicated "optimal" color. No allowance is made, in particular, for the fact that there are different gradations of red, for example, and that the red color on the lure may not actually match that closely the "optimal" red color identified by the prior art procedure. Nor do these prior art approaches impart useful information to the fisherman concerning the effectiveness of a lure that includes a combination of colors.
Another difficulty with each approach described hereinabove is that no adequate provision is made for the different action of non-fluorescent and fluorescent colors. Even Hill, who recognizes this difference, assumes that the fisherman will be able to accurately discriminate between lures of non-fluorescent and fluorescent color or between particular fluorescent shades that appear the same but that are formed of different color components. This assumption, however, is likely to be incorrect. It is a common practice among steelhead fishermen, for example, to use large amounts of "homemade" lures, composed of feathers, beads, yarn, colored tape, painted metal, and home-prepared baits, with little or no thought given as to quality control over the dye lots used. Furthermore, salmon and steelhead eggs are often prepared at home using combinations of salt, borax, sulfide, commercial homemade red dyes, brown sugar or even strawberry jello in order to preserve and color them. The average fisherman for these types of fish has no idea if the red coloring that is exhibited by his fishing lures is fluorescent or non-fluorescent. He has no idea of the color balance of any dye preparations he is using. A dye preparation may look red-orange but actually be composed of fluorescent yellow pigments mixed with non-fluorescent red pigments. Such a dye might look red-orange in the air but shift to an undesirable gray-yellow in the absence of red-orange light. It should also be recognized that one of the reasons homemade lures are popular for steelhead, salmon and other anadromous fish is because the rapidly moving water in which these types of fish are normally found results in a large number of snags and lost lures. This, in turn, is yet another reason why the fisherman is unlikely to have on hand a lure of precisely the "optimal" lure color.
In accordance with the foregoing, a principal object of at least a preferred embodiment of the present invention is to provide an improved system for evaluating a fishing lure for underwater effectiveness which is universally applicable to all types of fishing lures including homemade lures of unknown pigmentation.
A related object of at least preferred embodiments of the present invention is to provide an evaluation system that does not require the fisherman to determine whether his lure is fluorescent or non-fluorescent or what particular balance of dye components create the apparent color of the lure.
A further object of at least preferred embodiments of the present invention is to provide a system that evaluates accurately the underwater effectiveness of a fishing lure yet is simple to operate without the need for cumbersome, expensive and easily-damaged equipment.